Hi. Sorry I haven't done a formal intro but I wanted to get a few things posted that might help a few folks. Anyhow, I'm Dutch from Chattanooga, actually just across the state line in GA.
I have noticed several postings, not just here but on other forums as well, about chain rub on wide tires. I just finished installing a kit on a Huffy Cranbrook Cruiser from Walmart. My kit came with a heavy duty chain and sprocket and there was no dish in the sprocket. After installing the sprocket I did a quick temp install of the engine (rear mount only as I had to fabricate a front one) just to see if the chain was going to rub the tire. Sure enough, it did. Took the sprocket back off and made a spacer to go behind it out of saddle leather (about 3/16" thick) with the center hole the same size as was in the sprocket with the outer diameter to fit inside the bolt patern. I wanted the pressure to ride on the hub flange instead of the spokes. This gave me about 1/16" clearence between the chain and the tire. I finally realized that the rubber donut that goes on inside the spokes was adding additional pressure to the spokes causing the wheel to dish to the engine sprocket side. I loosened all the spokes on the engine sprocket side one full turn. I now have almost 1/4" clearence and still have plenty of tension on the spokes. I will have to do another adjustment on the sprocket as the leather compresses, but, hey, you work with what you have. The sprockets line up and the chain stays on. With fabricated front mounts you can shift the engine a bit from side to side to help with alignment. One cause of the problem was the cheap tires on the bike. When I let the air out to check for tube overlaps and to straighten the valve stems I noticed the side walls are thin as paper. But, what can you expect on a new bike that is $80 brand new out of the box.
This thin rubber will allow the side walls to expand farther, especially when they are pinched together on 1" wide rims. When I get around to getting a decent pair of tires I will probably have a little more clearence. I modified the fender by bending the outer flange in just enough to clear the chain and still have plenty of clearence between the fender and tire.
Till Later
Dutch
